The essence of the budget deal reached by Sen. Patty Murray, D-Wash., and Rep Paul Ryan, R-Wis., is better understood by looking at what's missing, rather than what's included in it.

The agreement by the budget committee chairmen is no grand bargain. It's more like a minibargain. And all the missing elements are absent precisely because the yawning ideological rift between Washington Democrats and Republicans made it impossible to include those items and still have the votes to get to "yes" and avoid a government shutdown in mid-January.

In short, it's the really hard stuff that didn't make it into the agreement.

So what's missing? Plenty. Here are some of the holes:

Unemployment insurance extension—Democrats had wanted an extension of unemployment insurance for the long-term unemployed in the deal. But Republicans resisted. So an extension isn't in the deal. Democrats hope one can be negotiated outside the Murray-Ryan minibargain. This is the season for hope, after all, though it all probably feels like a lump of coal in the the stocking if you're one of those long-term unemployed.

Taxes— Republicans were adamant that any deal couldn't raise revenue through new taxes, so there are none. Instead, the deal raises money to offset reduced sequester cuts through new or higher fees. For instance, the deal essentially raises the maximum aviation security fee a passenger pays for a one-way flight to $5.60 from $5. So flying just got a little more expensive.

Tax extenders— There are more than 60 tax provisions set to expire on Dec. 31, largely business tax breaks, according to the Tax Policy Center's TaxVox blog. Congress has routinely extended these in the past but the Murray-Ryan budget deal is silent on them. That's another area where the budget negotiators kicked the can down the road.

Entitlement reform—Republicans, mainly, had sought something in the deal to slow the increasing pressure on federal spending from the rising costs of Medicare and Social Security caused by all those aging baby boomers. That's a nonstarter for many Democrats, so long as Republicans refuse to consider higher taxes on the wealthiest and corporations.

Postal savings— Some budget experts saw the Murray-Ryan negotiations as a good chance for Congress to achieve savings through more austerity for the Postal Service, such as ending Saturday delivery. But such actions have proved unpopular with many voters, so the Murray-Ryan budget negotiators avoided that hornet's nest altogether.

Doc fix— When negotiations started, health care providers were among those hoping that the Murray-Ryan budget negotiators would solve the perennial threat that Medicare will slash its reimbursements to physicians. That would be the "doc fix" you hear so much about in Washington. Alas, the deal contains no doc fix. That will have to come from elsewhere in Congress.